title: E. coli Nissle 1917 Affects Salmonella adhesion to porcine intestinal epithelial cells.
abstract: BACKGROUND
  The probiotic Escherichia coli strain Nissle 1917 (EcN) has been shown to interfere in a human in vitro model with the invasion of several bacterial pathogens into epithelial cells, but the underlying molecular mechanisms are not known.
  
  
  RESULTS
  In this study, we investigated the inhibitory effects of EcN on Salmonella Typhimurium invasion of porcine intestinal epithelial cells, focusing on EcN effects on the various stages of Salmonella infection including intracellular and extracellular Salmonella growth rates, virulence gene regulation, and adhesion. We show that EcN affects the initial Salmonella invasion steps by modulating Salmonella virulence gene regulation and Salmonella SiiE-mediated adhesion, but not extra- and intracellular Salmonella growth. However, the inhibitory activity of EcN against Salmonella invasion always correlated with EcN adhesion capacities. EcN mutants defective in the expression of F1C fimbriae and flagellae were less adherent and less inhibitory toward Salmonella invasion. Another E. coli strain expressing F1C fimbriae was also adherent to IPEC-J2 cells, and was similarly inhibitory against Salmonella invasion like EcN.
  
  
  CONCLUSIONS
  We propose that EcN affects Salmonella adhesion through secretory components. This mechanism appears to be common to many E. coli strains, with strong adherence being a prerequisite for an effective reduction of SiiE-mediated Salmonella adhesion.
authors.affiliation: Institut für Mikrobiologie und Tierseuchen, Freie Universität Berlin, Berlin, Germany. Peter.Schierack@HS-Lausitz.de
authors.forename: Peter
authors.initials: P
authors.lastname: Schierack
authors.forename: Sylvia
authors.initials: S
authors.lastname: Kleta
authors.forename: Karsten
authors.initials: K
authors.lastname: Tedin
authors.forename: Julius Tachu
authors.initials: JT
authors.lastname: Babila
authors.forename: Sibylle
authors.initials: S
authors.lastname: Oswald
authors.forename: Tobias A
authors.initials: TA
authors.lastname: Oelschlaeger
authors.forename: Rico
authors.initials: R
authors.lastname: Hiemann
authors.forename: Susanne
authors.initials: S
authors.lastname: Paetzold
authors.forename: Lothar H
authors.initials: LH
authors.lastname: Wieler
mesh_terms: D000818:Animals; D000898:Antibiosis / Q000502:physiology; D001422:Bacterial Adhesion / Q000502:physiology; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000378:metabolism / Q000382:microbiology* / Q000473:pathology; D004926:Escherichia coli / Q000254:growth & development / Q000502:physiology*; D004927:Escherichia coli Infections / Q000150:complications / Q000382:microbiology / Q000662:veterinary; D015964:Gene Expression Regulation, Bacterial; D007413:Intestinal Mucosa / Q000378:metabolism / Q000382:microbiology* / Q000473:pathology; D012481:Salmonella Infections, Animal / Q000150:complications / Q000382:microbiology; D012486:Salmonella typhimurium / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D013045:Species Specificity; D013552:Swine / Q000382:microbiology / Q000502:physiology; D013553:Swine Diseases / Q000382:microbiology / Q000473:pathology